1. Field of the Invention
The present invention relates to a color image forming device, and more particularly to a color image forming device that includes a rotary developing device for rotating a plurality of developing units for development, and a toner container located apart from the developing device from which toner is supplied to the developing units.
2. Background Information
A color image forming device includes a plurality of developing units corresponding to a plurality of color toners. The developing units are arranged in several ways, such as in a lateral direction, around the photosensitive drum in a circumferential direction, and within a rotary frame located adjacent to the photosensitive drum.
The rotary developing device having a plurality of the developing units within the rotary frame is shown in Japanese Unexamined Patent Publication No. 62-182768. In this device, the rotary frame is rotatably located adjacent to the photosensitive drum, and supports four color developing units. When the rotary frame is rotated, each of the developing units is sequentially placed opposite the photosensitive drum so as to develop each color.
In addition, other types of the rotary developing device have been proposed so as to reduce the size of the rotary frame, for example, in Japanese Unexamined Patent Publications No. 10-198149 and No. 2001-134045. The rotary developing device includes a toner container located apart from the developing units supported by the rotary frame. In this device, the toner is supplied from the toner container to the developing units through a toner supply device including toner supply pipes.
In the device, the toner container is located separate and apart from the developing device so that the developing units are downsized and the rotary frame is also downsized. However, it is necessary to ensure a space for the toner container, otherwise the image forming device as a whole may grow in size even though the rotary frame itself is reduced in size. In this respect, the device shown in Japanese Unexamined Patent Publication No. 2001-134045 includes a toner container located at an axial end of the rotary developing device so as to provide a long axial length, although Japanese Unexamined Patent Publication No. 10-198149 does not show the specific location of the toner container.
In the image forming device, a fixing device is typically composed of a fixing roller having a heat source and a pressing roller. In the image forming process, it is necessary to keep the fixing roller at a high temperature to fix the toner image to the transfer sheet, thereby generating radiant heat. In addition, a driving motor for driving the photosensitive drum generates heat in the imager forming process. These heat sources increase temperature in the image forming device, and thus the quality of formed images and the lifespan of the mechanical components in the image forming device might be affected. In particular, some image forming devices are downsized and the layout in the device is restricted so that low heat resistance components and heat sources may be located close together.
In order to solve the problem, in the device shown in Japanese Unexamined Patent Publication No. 2000-98860, heat from the fixing device is exhausted so as to prevent the temperature in the image forming device from increasing and improve the quality of the formed image. In the device shown in Japanese Unexamined Patent Publication No. 2000-98860, an exhausting means is provided to guide the heat generated by the fixing means to a conveyance path located above the fixing means by means of natural convection. Although it is possible to exhaust the heat from the fixing means in this device, it is necessary to further prepare a cooling duct for exhausting the heat from other heat sources, and thus it is difficult to further reduce the image forming device in size.
It is an object of the present invention to reduce the size of the rotary developing device without letting the image forming device grow in size.
It is another object of the present invention to reduce the image forming device in size and cost by exhausting the heat from the heat sources through a minimum space for cooling.